Selective plasmalogen substrate utilization by thrombin-stimulated Ca2+-independent PLA2 in cardiomyocytes

Jane McHowat, Michael H. Creer

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

Thrombin stimulation of rabbit ventricular myocytes activates a membrane-associated, Ca2+-independent phospholipase A2 (PLA2) capable of hydrolyzing plasmenylcholine (choline plasmalogen), plasmanylcholine (alkylacyl choline phospholipid), and phosphatidylcholine substrates. To identify the endogenous phospholipid substrates, we quantified the effects of thrombin stimulation on diradyl phospholipid mass and arachidonic acid and lysophospholipid production. Thrombin stimulation resulted in a selective decrease in arachidonylated plasmenylcholine, with no change in arachidonylated phosphatidylcholine. The decrease in arachidonylated plasmenylcholine was accompanied by an increase in plasmenylcholine species containing linoleic and linolenic acids at the sn-2 position. A decrease in arachidonylated plasmenylethanolamine was also observed after thrombin station, with no concomitant change in arachidonylated phosphatidylethanolamine. Thrombin stimulation resulted in the selective production of lysoplasmenylcholine, with no increase in lysophosphatidylcholine content. There was no evidence for significant acetylation of lysophospholipids to form platelet-activating factor. Arachidonic acid released after thrombin stimulation was rapidly oxidized to prostacyclin. Thus thrombin-stimulated Ca2+-independent PLA2 selectively hydrolyzes arachidonylated plasmalogen substrates, resulting in production of lysoplasmalogens and prostacyclin as the principal bioactive products.

Original languageEnglish (US)
Pages (from-to)H1933-H1940
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume278
Issue number6 47-6
DOIs
StatePublished - Jun 2000

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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